;(function(win) {
  var tid;
  function refreshRem() {
    let designSize = 1440; 
    let html = document.documentElement;
    let wW = html.clientWidth;
    
    let rem = wW * 100 / designSize; 
    document.documentElement.style.fontSize = rem + 'px';
  }
 
win.addEventListener('resize', function() {
  clearTimeout(tid);
  tid = setTimeout(refreshRem, 300);
}, false);
win.addEventListener('pageshow', function(e) {
  if (e.persisted) {
    clearTimeout(tid);
    tid = setTimeout(refreshRem, 300);
  }
}, false);

refreshRem();

})(window);
